South Pole Neutron Detectors Could Forecast Solar Storms

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South Pole Neutron Detectors Could Forecast Solar Storms

Image: NASA/SDO/@Camilla_SDO

By Duncan Geere, Wired UK

Solar storms are notoriously difficult to predict, but a new application of the South Pole's neutron sensors could help humanity take shelter.

[partner id="wireduk"]These detectors are normally used to estimate the rate at which cosmic rays strike the Earth's atmosphere, slam into the nuclei of the gas atoms floating around up there, and send the neutrons within spinning towards the surface.

However, a team of space physicists has spotted that they could also be used as an early warning system by detecting incoming protons from solar storms. They compared the detectors' data with data collected from radiation sensors on an Earth-orbiting satellite during a series of particularly strong solar flares which occurred between 1989 and 2005, and found that they could predict the intensity of the storm.

Here's how they do it. From the neutron data, the team is able to work out the number of protons arriving with energies between 165 million and 500 million electron volts (which arrive at the sensors, on average, 95 minutes after the first protons of a flare reach Earth) and the number of slower-moving protons arriving with energies between 40 million and 80 million electron volts (which tend to arrive, on average, 71 minutes later).

By comparing the ratio of those numbers, the team can then estimate the maximum amount of radiation damage that the flare might bring, allowing them to send warning signals to space agencies, so they can shut down satellites or tell astronauts to take cover.

"This is a very interesting and very intriguing piece of work," said Louis Lanzerotti, a space physicist at the New Jersey Institute of Technology in Newark. He added that the technique provides "one more arrow in the quiver" of scientists looking to predict space weather. "This lets scientists estimate reasonably well what peak [radiation] intensity will be," he said.

Longer-term, crewed interplanetary craft could be protected by miniaturised sensors of the same type installed on a spaceship's hull.